The invention relates to an element for forming photographic images. It particularly relates to the combination of emulsion sensitization and absorbing dyes for color paper.
Color photographic paper is used in a wide variety of photoprocessing machines, which include large-scale processors capable of providing large volumes of photographic prints under conditions of continuous operation, and small-scale processors that are used to produce smaller volumes of photographic prints under conditions of discontinuous operation. These machines are known to differ widely in mechanical design, and the operating conditions for these processors vary widely in ambient temperature and humidity due to the wide variety of environments for use.
To provide a color photographic paper that serves all the different machines and conditions and is tolerant of the wide fluctuations in environment, one must address the variation of color paper performance to changes in heat and humidity at the site of operation. One aspect of these variations relates to the sensitivity of the photographic paper to changes in temperature. It is desirable to make photographic materials that are invariant to any changes in environmental temperature, such that the photographic response does not change when the ambient temperature fluctuates during the course of processor operations. Alternatively, satisfactory results can be achieved when the photographic response is neutral with respect to changes in environmental temperature, that is, although the photographic material may have a different response as the temperature changes, the changes are not noticeable to the operator as the effects of temperature in each of the constituent layers are synchronized to annul the effect of the temperature changes.
In the manufacture of color photographic paper it is critical to maintain the activity of the photographic components such that the photographic response does not change during the course of manufacturing. To ensure a consistent outcome is obtained, it is necessary to monitor photographic activity in the process of manufacturing. During the course of manufacturing, many incidental changes can occur and impact photographic response characteristics such as photographic speed. These speed changes can be measured during the manufacturing process, and adjustments can be made to maintain a consistent response. It is of enormous benefit to the process of manufacturing photographic materials if adjustments to the levels of the components bear a linear response to the speed value. Additionally, it is obvious that if less material is utilized in obtaining the desired photographic effect, cost advantages can be accrued.
Advantages gained in the manufacture of color paper cannot be realized if photographic performance is jeopardized. Therefore, it is desired that manufacturing gains be made concomitantly with gains in photographic performance. It is known that heat sensitivity of the photographic material is critical to its acceptability for use, and that changes in heat sensitivity can occur when changes are made in the process of manufacturing; thus, it is highly desirable that manufacturing changes do not degrade heat sensitivity.
It is intended that color photographic paper satisfy the desires of photographers in the practice of their art. In the hands of the photographer, it is common practice to regulate the exposure of photographic material under conditions where some areas of the print may receive greater light exposure than a normal exposure to xe2x80x9cburn inxe2x80x9d the desired image to a greater degree. Alternatively, it is also the practice to shield some areas of the print from normal exposure to light, and by xe2x80x9cdodgingxe2x80x9d the light in this way create the desired image. Color papers also vary in their undeveloped color from batch to batch, as different absorber dyes are added to adjust their properties. In practicing the techniques of dodging and burning, the photographer or enlarger operator is hindered by a color photographic material that has a dark color content prior to exposure. This makes the dodging and burning more difficult, as the paper looks different during exposure as the undeveloped paper color is different.
There is a need for photographic paper that is more easily adjusted to control speed and sensitivity during manufacturing without demonstrating increased heat sensitivity.
It is an object of the invention to overcome disadvantages of prior photographic elements.
It is a further object of the invention to provide a color paper that is easier for the printer operator to accurately dodge and burn during printing.
A further object of the invention is to provide a color paper that has the sensitometric and speed properties adjusted during manufacturing without significantly changing the color of the undeveloped paper.
A further object of the invention is to provide a color paper that has the ease of dodging and burning,the sensitometric and speed adjustment capability during manufacture and does not have an increase in heat sensitivity.
An additional object of the invention is to provide lower manufacturing cost for color papers.
These and other objects generally are accomplished by providing a photographic element comprising at least one absorber dye and at least one sensitizing dye wherein the wavelength of maximum sensitivity of said absorber dye and the wavelength of maximum sensitivity of the emulsion provided by the spectral sensitizing dye are substantially the same and where the emulsion is chemically sensitized with an organomercapto Au(I) complex having the formula
[Lxe2x80x94Auxe2x80x94L]M
wherein the complex is symmetrical; L is an organomercapto ligand which is an antifogging, stabilizing or sensitizing compound, and M is a cationic counter ion. In a preferred embodiment of the invention the the silver halide grains of the emulsion contain one or more dopants as described in copending application Ser. No. 09/420,746, filed concurrently herewith, the entire disclosures of which are incorporated herein by reference. The wavelength of maximum absorbance of the absorer dye and the wavelength of maximum sensitivity f the sensitized emulsion are substantially the same. The term xe2x80x9csubstantially the samexe2x80x9d means that the wavelength of maximum absorbance of the absorber dye is within about 15 nm, preferably within about 10 nm and most preferably within about 5 nm of the wavelength of maximum sensitivity of the sensitized emulsionl
An advantage of the invention is that color papers are produced that are easier to control as to sensitivity and speed during manufacturing.